Clinical trials and human sexuality: basic concepts and problems

In considering the evaluation of pharmacological agents in the treatment of sexual dysfunction, four fundamental issues are discussed in this paper: (1) most pharmacological agents which have been used for this purpose act on neurotransmitter systems which are not specific to sexual response; (2) even when a sexually relevant pharmacological effect can be assumed, its effect on sexual behavior will be modulated by information processing; (3) the first attempts to evaluate the agent should focus on direct effects on the individual receiving the drug; and (4) evaluation of the relevance of the direct pharmacological effect on the well-being of a sexual relationship requires control of the considerable variance which exists in the capacity for change in sexual relationships.